1. Field of the Invention
The present invention relates generally to the tilt monitoring field and, more particularly, to a method and apparatus for bi-axial tilt monitoring using a single-axis tilt monitoring device.
2. Description of the Related Art
Many products are susceptible to being damaged by excessive tipping, and are particularly vulnerable to excessive tipping during shipping. For example, in the data processing field, products such as large servers, storage systems, tape libraries and enterprise printers cannot survive being tipped onto their sides or top, and if any of these products do tip over, the financial loss due to the resulting damage is often significant.
Because of the risk of financial loss due to tipping over, it is known to mount a tilt monitoring device to such products during shipping in order to monitor the products. The tilt monitoring device can include a date/clock function so that it can be determined not only if a damaging tipping has occurred, but when the tipping occurred so that the responsible party can more easily be identified for damage claim purposes and root cause analysis.
A known tilt monitoring device is the “Tilt Monitor Card” available from Kuroda Electric Co. Ltd., often referred to as a “TMC”. The TMC utilizes a small, electrically conductive disk that slides out of position when the device is tilted more than 70 degrees from vertical and alters an electrical circuit in the device. Altering the circuit causes a digital clock in the device to freeze so as to indicate the precise time at which the excessive tilt event occurred.
The TMC tilt monitoring device is used by mounting it to a vertical surface of an article to be monitored, for example, on a product itself or on packaging containing the product. This is typically done prior to shipping of the article, and indicates whether the article was excessively tipped at any time during shipping.
The TMC tilt monitoring device, however, is a single-axis tilt monitoring device that is only able to detect tipping of an article around a single axis. In order to effectively monitor tipping at all angles, however, an article should be monitored for tipping around two axes. This problem is typically addressed by mounting two TMCs to two adjacent vertical surfaces of the article which are perpendicular to one another. For instance, one TMC placed on the left or right side of the article will monitor tipping onto its front or back side, and a second TMC, placed on the front or back side of the article will monitor tipping onto its right or left side. This solution, however, doubles the cost of monitoring an article, and can result in very significant additional expense when a large number of articles are shipped.
A bi-axial tilt monitoring device that monitors tilt around two axes is known that uses small beads to detect tilt. However, this known device does not include a date/clock function to indicate when an excessive tipping of a product occurred.
There is, accordingly, a need for a low cost bi-axial tilt monitoring apparatus that effectively detects tipping of an article in all directions, and that also includes a date/clock function to precisely indicate the time when an excessive tipping event occurs.